Head elevation by 3 vs. 6cm in ProSeal laryngeal mask airway insertion: A randomized controlled trial

Abstract

Background: The sniffing position (neck flexion by head elevation and head extension) is commonly used for insertion of a laryngeal mask airway. However, the appropriate degrees of head elevation and head extension are unclear. In the present study, the success rate of ProSeal™ laryngeal mask airway (LMA ProSeal) insertion using two degrees of head elevation was evaluated. Methods: This prospective randomized, controlled study included 80 adult patients aged 18 to 90years. In the 3cm (n=40) and 6cm (n=40) groups, the LMA ProSeal was inserted while the head was elevated 3cm and 6cm, respectively, using a pillow of the corresponding height. The success rate, and incidence of blood staining on cuff, sore throat and hoarseness were assessed. The alignments of laryngeal and oral axes were also evaluated. Results: The first attempt success rate was higher in the 3cm than the 6cm group (87% vs. 60%, P=0.014). In 86% of patients in the 6cm group and 50% of patients in the 3cm group in whom the second attempt failed, the third insertion attempt was successful by using a pillow height of the opposite group. The alignments of the two axes were not different between the two groups (P>0.05). Conclusions: The first attempt success rate of ProSeal laryngeal mask insertion was higher with 3cm than 6cm head elevation in adult patients. Trial registration: Identifiers: NCT02058030(08/05/2015), Unique Protocol ID: phdkim1.